| 摘要 |
PROBLEM TO BE SOLVED: To reduce the number of terminals of a power supply control IC and the number of outside-IC components in a switching power supply circuit. SOLUTION: A synchronous detection circuit which is composed of outside-IC components in a conventional constitution is built in an IC. The inputs of the synchronous detection circuit 14 are supplied from the collectors of the transistors of a differential circuit 13 and a synchronous pulse is generated by using, for instance, a comparator. The synchronous pulse is converted into a rectangular wave by an oscillation circuit 12 and the transistors of the differential circuit 13 are switched alternately. |
